1. Field of Invention
The present invention relates to a projection screen.
2. Description of Related Art
Currently, projection screens generating stereoscopic images with lens pupil scanning method are mostly transmission screens. FIG. 7 is a schematic diagram of a conventional transmission projection screen. In general, the transmission projection screen includes a Fresnel lens 910, double lenticular lenses 920 and 930, and a diffuser 940. The Fresnel lens 910 converges the diffusing light emitted from a projector (not shown) to parallel light, and the lenticular lens 920 images the parallel light onto the diffuser 940. Subsequently, the lenticular lens 930 images the images on the diffuser 940 to different views. This method faces problems such as the Fresnel lens 910 itself refracts different color lights (such as red, blue, and green lights) to different positions due to its chromatic aberration, such that the lights are unable to be projected on the correct views. For an image system including the lenticular lens 920, the F number must be greater to maintain an acceptable image quality. Therefore, the back focus of the lenticular lens 920 is increased, resulting in a large screen thickness. Moreover, since the Fresnel lens 910 is a thin lens composed by many tiny surfaces, which generates moire with the lenticular lenses 920 and 930. The diffuser 940 decreases the image quality, thereby creating a deteriorating crosstalk problem. In addition, the diffuser 940 repeats views, and as a result, view reversion area unavoidably occurs on the projection screen.